Japanese Patent No. 4490213 discloses a conventional technology in this headrest field. A headrest described in this prior art includes a foam padding and a stay supported on a seat, the stay being at its upper portion embedded in the foam padding. This stay is formed by: a pair of leg portions which are exposed from the foam padding and extend in a predetermined spaced-apart and parallel relation with each other; and an inverted-U-shaped load receiving portion defined between those two leg portions at an upper region of the stay. The foam padding consists of one foam padding element having a normal-repulsive elasticity and another foam padding element having a low-repulsive elasticity. A process for forming this kind of headrest entails: providing a three-dimensional trim cover element; attaching a low-repulsive foam padding element to a forwardly-facing inner surface of that three-dimensional trim cover element; inserting the aforesaid stay in the trim cover assembly; placing the thus-prepared trim cover element in a foaming die; injecting a liquid foaming agent, such as a liquid urethan foaming agent, in the trim cover element; and curing the liquid foaming agent to create an increased mass of a foam padding element having a normal-repulsive elasticity. As a result thereof, a headrest is formed, which has the normal-repulsive foam padding element and the low-repulsive foam padding element, in a manner integral with the trim cover assembly. The provision of such low-repulsive foam padding element in the forwardly-facing side of the headrest is effective for preventing a deep sinking or recession of the corresponding padding region of the headrest which is caused by contact of a passenger's head therewith and also effective for suppressing a subsequent great rebound of the passenger's head from that particular padding region of the headrest.